Patent GB-1267103-A (GB)
IPC: H01J31/22
Filed: 1969-11-03
Abstract: 1,267,103. Stereoscopic colour television. A. J. GALE. 3 Nov., 1969 [22 Nov., 1968], No. 83836/69. Heading H4F. [Also in Division H1] A cathode-ray display tube comprises an array of cells each containing a cathode disposed opposite a fluorescent screen. In Fig. 7, each cell 23 is of rhombic cross-section and is bounded by insulating walls 41-43. The cathode structure comprises rows of aluminium conductors 27 on an insulating base 29 and covered by SiO 2  insulation 31 on which are arranged columns of gold conductors 26 so that when a potential of about 200 volts is applied between a conductor 26 and a conductor 27, electrons are emitted from the crossing point. The emission may be controlled by rows of hori. zontal grid conductors 44 which are switched sequentially, and by columns of vertical grid conductors 46 which are sequentially biased by picture signals to modulate the electron streams. Alternatively, one or both sets of grids may be omitted (Figs. 4 and 6, not shown) and the scanning and modulation are then performed through the conductors 26 and 27 and the remaining grids (if present). The fluorescent screen may comprise an array of phosphor dots 28 and an interconnecting conductive film 34 on a face-plate 35. In colour display the dots may be of different colours, or alternatively an array of colour filters 36 may be disposed between the dots and the face-plate; in the latter case the dots may be white or the screen may be continuous, and this construction is also suitable for monochrome operation when the filters are omitted. The whole display device may be in the form of a rectangular box having a depth about one-tenth of its width. Stereoscopic colour display, Fig. 15.-The colour filters covering the individual cells of the display are arranged as shown and include filters for the primary colours R, G and B and filters which split these colours into high and low wavelength ranges such as R R  and R B  for the red. The lines are scanned in pairs with interlacing as shown so that the pairs of lines L1, L2 &c. are scanned in one frame and the alternate pairs of lines AL1, AL2 &c. on the next frame; the pairs denoted by odd numbers in both sets are taken from one camera, and the even pairs from an adjacent camera focused on the same scene. The display is viewed through filters R R , G R  and B R  for one eye and R B , G B  and B B  for the other eye, and the areas R, G and B are preferably attenuated 50% by filters to equalize the light flux when the display is observed directly. An alternative arrangement which requires more picture elements, Fig. 16 (not shown), comprises three lines using only R R , G R  and B R  alternating with three lines using only R B , G B  and B B . Scanning arrangements, Fig. 12.-The horizontal conductors 27 are connected through semi-conductor switches 69 to terminal points 70 which are sequentially switched; in alternate frames all the switches 69b or all the switches 69c are open to provide the interlacing, the lines being scanned in pairs as described above with reference to Fig. 15. The vertical conductors 26 are connected to field effect transistors 71 which are connected in threes via further transistors 73 to terminals 75. Transistors 73 are normally non-conducting and are made conducting by luminance signals which are applied in sequence to terminals 75; the current flow through them is divided through transistors 71 in accordance with the chrominance signal applied to them via terminals 72. In a modified circuit (Fig. 13, not shown), suitable for the display illustrated in Fig. 16 (not shown), each line 27 is connected through only one transistor to a single terminal 70, and each line 26 is connected through a transistor 71, the transistors 71 being connected in threes coupled through a transistor to a terminal 75.